Reliability centred maintenance

ABSTRACT

A maintenance method and apparatus based on reliability centered maintenance, applied for example to a military aircraft, include the following steps performed in a feedback manner: i) performing RCM; ii) feeding outcomes derived from performing the RCM to an update process; iii) performing the update process to provide update data for performing the RCM; and iv) inputting the update data into the performing of the RCM. The method can carry out a maintenance action selected by and/or or at a time and/or extent specified by the performing of the RCM; the outcomes that are fed to the update process including outcomes from the maintenance action that is carried out. The maintenance method thereby can provide a continuously updating RCM process.

FIELD OF THE INVENTION

The present invention relates to reliability centred maintenance (RCM),and is particularly applicable to, but not limited to, the use of RCMfor military aircraft.

BACKGROUND

Maintenance regimes for systems and equipment can be scheduled andcarried out in many conventional ways, for example specific selectedmaintenance actions such as replacing or testing a component of avehicle can be carried out at fixed time intervals or fixed operationaltime intervals.

For complex and/or safety-critical systems, for example passengeraircraft and military aircraft, it is known to use a systematic,“holistic” maintenance approach known as reliability centred maintenance(RCM). Although in one sense any maintenance can be considered asimproving reliability, it will be appreciated by the person skilled inthe art of maintenance of complex and/or safety-critical systems thatthe terminology “reliability centred maintenance” defines specific typesof recognised large scale preventive maintenance processes. Examples ofrecognised RCM processes are “Operator/Manufacturer ScheduledMaintenance Development—MSG-3” (published by the Air TransportAssociation of America, Inc. (ATA)) and “Procedures for DevelopingPreventive Maintenance—AP100C-22” (published by the Royal Air Force(RAF) and available from the Defence Storage and Distribution Centre(DSDC), LLangennech, UK). Conventionally, a bespoke RCM program or planis produced for a specific aircraft type/scenario combination, where thescenario may be, for example, one or more of intended deployment mode,specification of variable parameters/components of the aircraft,customer identity, and so on. Preventive maintenance actions, such asreplacing or testing a component of the aircraft, are then selectedaccording to the RCM output and carried out at times and/or to extentsdetermined by the output of the RCM program.

It is known to provide software that implements or controls some or allof the RCM. This software, or other forms of implementation, and itsoperation, may be known as an RCM toolset.

Parts of the RCM process are carried out and/or managed by humanoperators. Control of the operation of the human operator in theirefforts to implement processes as part of RCM may be known asgovernance. In respective application areas, e.g. one being for civilaircraft, a different one being for military aircraft, correspondingrespective governance arrangements are either specified as part of RCMor have become common practice when implementing RCM in that particularrespective application area. Hence, for example, conventionallygovernance for RCM for military aircraft is considered to be completelydifferent to, and incompatible with, governance for RCM for civilaircraft, and also completely different to, and incompatible with,governance for other industries such as the oil industry, nuclearindustry, and so on.

SUMMARY OF THE INVENTION

In a first aspect, the present invention provides a maintenance methodbased on reliability centred maintenance (RCM); the maintenance methodcomprising the following steps performed in a feedback manner: i)performing RCM; ii) feeding outcomes derived from performing the RCM toan update process; iii) performing the update process to provide updatedata for performing the RCM; and iv) inputting the update data into theperforming of the RCM.

The method may further comprise carrying out a maintenance actionselected by the performing of the RCM; and wherein the outcomes derivedfrom performing the RCM that are fed to the update process compriseoutcomes from the maintenance action that is carried out.

The method may further comprise carrying out a maintenance actionperformed at a time specified by the performing of the RCM; and whereinthe outcomes derived from performing the RCM that are fed to the updateprocess comprise outcomes from the maintenance action that is carriedout.

The method may further comprise carrying out a maintenance actionperformed to an extent specified by the performing of the RCM; andwherein the outcomes derived from performing the RCM that are fed to theupdate process comprise outcomes from the maintenance action that iscarried out.

The update process may comprise one or more of the following processes:a baseline review process; a continuous review process; and an RCM studyprocess.

The update process may comprise a trigger mechanism process.

The outcomes from performing the RCM may be fed to the update processvia an identify preventive maintenance requirements process.

The outcomes from performing the RCM may be fed to the update processvia a maintenance repair organisation process.

The performed maintenance action may be performed as part of themaintenance repair organisation process.

The outcomes from performing the RCM may be fed to the update processvia a maintenance approved organisation process.

The maintenance method may thereby provide a continuously updating RCMprocess.

The maintenance method may be applied to a military aircraft.

In a further aspect, the present invention provides apparatus forperforming a maintenance method based on reliability centred maintenance(RCM); the apparatus comprising one or more processors arranged toperform the following steps in a feedback manner: i) performing RCM; ii)feeding outcomes derived from performing the RCM to an update process;iii) performing the update process to provide update data for performingthe RCM; and iv) inputting the update data into the performing of theRCM.

In a further aspect, the present invention provides a program orplurality of programs arranged such that when executed by a computersystem or one or more processors it/they cause the computer system orthe one or more processors to operate in accordance with the method ofany of the above aspects.

In a further aspect, the present invention provides a machine readablestorage medium storing a program or at least one of the plurality ofprograms according to the above mentioned aspect.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flowchart/block diagram of a conventional RCM process for amilitary aircraft;

FIG. 2 is a flowchart/block diagram of an overview of a continuous RCMprocess for military aircraft;

FIG. 3 is a flowchart/block diagram showing certain details of a triggermechanism process that is part of the continuous RCM process of FIG. 2;

FIG. 4 is a flowchart/block diagram showing certain details of abaseline review process that is part of the continuous RCM process ofFIG. 2;

FIG. 5 is a flowchart/block diagram showing certain details of acontinuous review process that is part of the continuous RCM process ofFIG. 2;

FIG. 6 is a flowchart/block diagram showing certain details of an RCMstudy process that is part of the continuous RCM process of FIG. 2;

FIG. 7 is a flowchart/block diagram showing certain details of anidentify preventive maintenance requirements process that is part of thecontinuous RCM process of FIG. 2;

FIG. 8 is a flowchart/block diagram showing certain details of amaintenance repair organisation process that is part of the continuousRCM process of FIG. 2;

FIG. 9 is a flowchart/block diagram showing certain details of amaintenance approved organisation process;

FIG. 10 is a flowchart/block diagram showing certain details of a designapproved organisation process that is part of the continuous RCM processof FIG. 2;

FIG. 11 is a flowchart/block diagram showing certain details of inputand output flows of a configuration control process that is part of thecontinuous RCM process of FIG. 2;

FIG. 12 is a flowchart/block diagram showing certain details of inputand output flows of a reliability analysis process that is part of thecontinuous RCM process of FIG. 2;

FIG. 13 is a block diagram of a control process/data flow forcontrolling aspects of the continuous RCM process of FIG. 2; and

FIG. 14 is a process flowchart showing certain steps of an RCMgovernance and maintenance actions process.

DETAILED DESCRIPTION

FIG. 1 is a flowchart/block diagram of a conventional RCM process 1 fora military aircraft. In this example the conventional RCM process 1 isone implemented for a military aircraft, and in which the implementationis at least substantially or approximately in line with the RCM standard“AP100C-22” referenced above.

Each block in FIG. 1 (and the following Figures) may be considered asrepresenting a process step in a flowchart, or equally as a functionalmodule of a system for implementing a process. It will be appreciated bythe person skilled in the art of RCM that RCM is a highly complexprocess, and the full detailed specification of any specific RCM programwould in practice usually require many thousands of pages or data sets,and accordingly the representations in FIG. 1 and all following Figures,and their associated descriptions, are by necessity in a simplifiedform. The person skilled in the art of RCM will be aware of this andwill accordingly be able to implement highly complexsystems/processes/programs based on these simplified descriptions, asthis by necessity is a skill routinely employed in this field.

The conventional RCM process 1 comprises various processes that mayconveniently be called as follows: a significant item selection process202, an analysis process 204, a quality assurance process 212, amaintenance working group process 214, and a maintenance review boardprocess 216.

(N.B. Also shown in FIG. 1 are inputs into the significant itemselection process 202, from a “process 4”, from a “process 5”, and froma “process 6”. These are relevant to how the conventional RCM process 1is incorporated in a continuous RCM process 20, as will be described inmore detail later below, and in which the “process 4” indicates abaseline review process 4, the “process 5” indicates a continuous reviewprocess 5, and the “process 6” indicates an RCM study process 6, as willbe described in more detail later below. In other words, the receipt ofinputs from a baseline review process 4, a continuous review process 5,and an RCM study process 6 is not as such part of conventionalstand-alone RCM processes, but is nevertheless shown in FIG. 1 forconsistency with the later description of how a conventional RCM processis used in the continuous RCM process that will be described laterbelow.)

Outcomes of the significant item selection process 202 are input in tothe analysis process 204, which in more detail comprises three types ofanalysis process, namely zonal analysis process 206, functionallysignificant item analysis process 208, and structurally significant itemanalysis process 210.

Outcomes of the analysis process 204 are input in to the qualityassurance process 212.

Outcomes of the quality assurance process 212 are input in to themaintenance working group process 214.

Outcomes of the maintenance working group process 214 are input in tothe maintenance review board process 216.

Accordingly, and in a manner well known to the skilled person, anoutcome of the maintenance review board process 216 is an RCM programthat specifies selected maintenance actions and schedules for thoseactions. Thus, as a result of the conventional RCM process 1,maintenance actions, for example replacing or testing a component of theaircraft are selected, scheduled and later carried out according to theschedule.

(N.B. Also shown in FIG. 1 is an output from the maintenance reviewboard process 216 to a “process 7”. This is relevant to how theconventional RCM process 1 is incorporated in a continuous RCM process20, as will be described in more detail later below, and in which the“process 7” indicates an identify preventive maintenance requirementsprocess 7, as will be described in more detail later below. In otherwords, the outputting to an identify preventive maintenance requirementsprocess 7 is not as such part of conventional stand-alone RCM processes,but is nevertheless shown in FIG. 1 for consistency with the laterdescription of how a conventional RCM process is used in the continuousRCM process that will be described later below.)

FIG. 2 is a flowchart/block diagram of an overview of an embodiment of amodified RCM process 20, hereinafter referred to as a continuous RCMprocess 20, for military aircraft. As will be explained in more detailbelow, as part of the continuous RCM process 20, the conventional RCMprocess 1 described above with reference to FIG. 1 is carried out in arepeated manner along with many new additional processes and steps thatbroadly speaking either use outputs of the conventional RCM process 1 orproduce updated inputs for the conventional RCM process 1, in the mannerof one or more feedback loops.

Each repeated loop of the continuous RCM process 20 is triggered by aprocess that may conveniently be called a trigger mechanism process 3(which will be described in more detail later below with reference toFIG. 3).

Outcomes of the trigger mechanism process 3 are input into one or morereviews and/or studies that are then performed, in this example oneswhich may conveniently be called a baseline review process 4, acontinuous review process 5, and an RCM study process 6 (which will bedescribed in more detail later below with reference to FIGS. 4 to 6respectively).

Outcomes of the reviews and/or studies are input into the conventionalRCM process 1.

The conventional RCM process is as described earlier above withreference to FIG. 1. It will be appreciated by the skilled person in theart that this will include any minor modifications, internalrepetitions, changes in data flow direction and so on that may berequired or may be found desirable in any given implementation, as aconsequence of the way in which the conventional process 1 isincorporated within this continuous RCM process 20. Any suchmodifications etc. will be readily implementable by the person skilledin the art of RCM, especially since in all practical implementations ofconventional RCM such modifications and the like are frequently requiredto be made to adapt to each particular RCM scenario.

Outcomes of the conventional RCM process 1 are input into a process thatmay conveniently be called an “identify preventive maintenancerequirements” process 7 (which will be described in more detail laterbelow with reference to FIG. 7).

Outcomes of the identify preventive maintenance requirements process 7are input into two processes, one being a process that may convenientlybe called a maintenance repair organisation process 8 (which will bedescribed in more detail later below with reference to FIG. 8), and theother being a process that may conveniently be called a configurationcontrol process 11 (which will be described in more detail later belowwith reference to FIG. 11).

It is noted that as part of the maintenance repair organisation process8, maintenance actions, for example replacing or testing a component ofthe aircraft, are selected, scheduled and later carried out according tothe schedule.

Outcomes of the maintenance repair organisation process 8 are returned,to provide a form of continuous feedback implementation, to the triggermechanism process 3. These outcomes will at least in part be used by thetrigger mechanism process 3 in triggering the next loop of thecontinuous RCM process 20. Outcomes of the maintenance repairorganisation process 8 are also input into a process that mayconveniently be called a maintenance approved organisation process 9(which will be described in more detail later below with reference toFIG. 9).

Outcomes of the maintenance approved organisation process 9 are inputinto the configuration control process 11. Outcomes of the maintenanceapproved organisation process 9 are also input into a process that mayconveniently be called a reliability analysis process 12 (which will bedescribed in more detail later below with reference to FIG. 12).

Outcomes of the reliability analysis process 12 are returned, to providea form of continuous feedback implementation, to the trigger mechanismprocess 3. These outcomes will at least in part be used by the triggermechanism process 3 in triggering the next loop of the continuous RCMprocess 20.

Another process that provides outcomes that are input into theconfiguration control process 9 is a process that may conveniently becalled a design approved organisation process 10 (which will bedescribed in more detail later below with reference to FIG. 10).

Outcomes of the configuration control process 11 are returned, toprovide a form of continuous feedback implementation, to the triggermechanism process 3. These outcomes will at least in part be used by thetrigger mechanism process 3 in triggering the next loop of thecontinuous RCM process 20.

FIG. 3 is a flowchart/block diagram showing certain details of thetrigger mechanism process 3. The trigger mechanism process 3 triggerseach repeated loop of the continuous RCM process 20. The triggermechanism process 3 comprises various processes that may conveniently becalled as follows: an operational issues process 32, a data analysisprocess 34 and a prioritisation process 36. The data analysis process 34and the prioritisation process 36 in combination provide a maintenancesteering group process 38.

The operational issues process 32 provides feedback from the operator ofthe aircraft (e.g. an air force) for faults that have been identifiedfrom the use of the aircraft. This may include system feedback reports,operator/discussions with the pilots, operational context informationand diagnostic data pertaining to the sortie of the aircraft.

Outcomes of the operational issues process 32 are input into the dataanalysis process 34. The outcomes from each of the maintenance repairorganisation process 8, the configuration control process 9, and thereliability analysis process 12 are also input into the data analysisprocess 34, providing a feedback loop operation.

The data analysis process 34 provides analysis of the operational,design and maintenance data. The data analysis process identifies andcodifies the key elements of information and provides a logical andhierarchical reporting mechanism of key issues impacting, for example,aircraft safety, operation and cost.

Outcomes of the data analysis process 34 are input into theprioritisation process 36.

The prioritisation process 36 comprises invoking of action to addressthe data analysis results from the data analysis process 34. Theprioritisation process 36 directs a course of sequenced action andresources to investigate the aircraft operating effects defined in thedata analysis process 34.

Thus the maintenance steering group process 38, which comprises the dataanalysis process 34 and the prioritisation process 36, in effect definesthe maintenance strategy for the aircraft platform on a continualimprovement basis using actuarial operational and maintenance data. Thismay include the whole aircraft fleet and individual squadrons.

Outcomes of the prioritisation process 36 (i.e. outcomes of themaintenance steering group process 38) are output from the triggermechanism process 3 for inputting to the baseline review process 4, thecontinuous review process 5, and the RCM study process 6. These outcomesare in effect directives to conduct a directed and precise method of RCManalysis, which is dependant on the actuarial data and operationalcontext.

FIG. 4 is a flowchart/block diagram showing certain details of thebaseline review process 4. The baseline review process 4 comprisesvarious processes that may conveniently be called as follows: adetermine project scope process 41, a determine hazardous operationanalysis process 42, a determine quality management structure process43, an implement a prioritisation process 44, a develop project planprocess 45, an allocate resource process 46, and a develop stakeholdersprocess 47.

The following stages of the baseline review process 4 are performed onprioritisation data and data analysis data that constitute “baselinedata” and has primarily originated from the operational issues process32 of the trigger mechanism process 3.

The determine project scope process 41 defines the scope, requirements,method and quality plan for the RCM project. The project scope isexplicit in defining the operational and organisation context in how theRCM project is being carried out.

Outcomes of the determine project scope process 41 are input into thedetermine hazardous operation analysis process 42.

The determine hazardous operation analysis process 42 comprisesperforming risk analysis and risk mitigation analysis. The process alsocomprises analysis of how the RCM process might fail, and how that wouldaffect the safety of the aircraft.

Outcomes of the determine hazardous operation analysis process 42 areinput into the determine quality management structure process 43.

The determine quality management structure process 43 comprisesdetermining training procedures and determining toolsets. Furtherdetails of aspects of the determination and control of trainingprocedures is given later below in a description of governance issues.Further details and examples of toolsets are also described later below.

Outcomes of the determine quality management structure process 43 areinput into the implement a prioritisation process 44.

The implement a prioritisation process 44 comprises prioritising, anddetermining details of, the program objectives. This comprises, forexample, a list of aircraft parts and respective lists of maintenanceactions that are to be taken with regard to each of those parts.

Outcomes of the implement a prioritisation process 44 are input into thedevelop project plan process 45.

The develop project plan process 45 comprises determining what has to bedone to facilitate and perform those maintenance actions, and whattimescales are relevant to them. In other words, this comprisesdetermining “what has to be done?”. Outcomes of the develop project planprocess 45 are input into the allocate resource process 46.

The allocate resource process 46 comprises allocating resources for theactivities determined in the preceding process. In other words, thiscomprises determining “how are the things that have to be done going tobe achieved?”.

Outcomes of the allocate resource process 46 are input into the developstakeholders process 47.

The develop stakeholders process 47 comprises determining which peopleor organisations will be responsible for which of the activities thathave been determined in the preceding steps. This may include trainingor relevant people. Such training may be implemented according to themethods and under the constraints of aspects given later below in adescription of governance issues.

Outcomes of the develop stakeholders process 47 are output from thebaseline review process 4 for inputting to the conventional RCM process1. These outcomes comprise, in effect, components of a quality plan forperforming conventional RCM.

FIG. 5 is a flowchart/block diagram showing certain details of thecontinuous review process 5. The continuous review process 5 comprisesvarious processes that may conveniently be called as follows: adetermine continuous improvement project scope process 51, a determinehazardous operation analysis process 52, a determine quality managementstructure process 53, an implement a prioritisation process 54, adevelop project plan process 55, an allocate resource process 56, and adevelop stakeholders process 57.

The following stages of the continuous review process 5 are performed onprioritisation data and data analysis data derived from data that hasbeen fed back to the data analysis process 34 from the maintenancerepair organisation process 8, the configuration control process 9, andthe reliability analysis process 12.

The determine continuous improvement project scope project process 51defines the specific and detailed requirements for the continuousimprovement RCM project. This may include a scope of safety analysis,operational context exclusions and a resource plan to satisfy aproactive RCM review.

Outcomes of the determine continuous improvement project scope process51 are input into the determine hazardous operation analysis process 52.

The determine hazardous operation analysis process 52 comprisesperforming risk analysis and risk mitigation analysis. The process alsocomprises analysis of how the RCM process might fail, and how that wouldaffect the safety of the aircraft.

Outcomes of the determine hazardous operation analysis process 52 areinput into the determine quality management structure process 53.

The determine quality management structure process 53 comprisesdetermining training procedures and determining toolsets. Furtherdetails of aspects of the determination and control of trainingprocedures are given later below in a description of governance issues.Further details and examples of toolsets are also described later below.

Outcomes of the determine quality management structure process 53 areinput into the implement a prioritisation process 54.

The implement a prioritisation process 54 comprises prioritising, anddetermining details of, the program objectives. This comprises, forexample, a list of aircraft parts and respective lists of maintenanceactions that are to be taken with regard to each of those parts.

Outcomes of the implement a prioritisation process 54 are input into thedevelop project plan process 55.

The develop project plan process 55 comprises determining what has to bedone to facilitate and perform those maintenance actions, and whattimescales are relevant to them. In other words, this comprisesdetermining “what has to be done?”. Outcomes of the develop project planprocess 55 are input into the allocate resource process 56.

The allocate resource process 56 comprises allocating resources for theactivities determined in the preceding process. In other words, thiscomprises determining “how are the things that have to be done going tobe achieved?”.

Outcomes of the allocate resource process 56 are input into the developstakeholders process 57.

The develop stakeholders process 57 comprises determining which peopleor organisations will be responsible for which of the activities thathave been determined in the preceding steps. This may include trainingor relevant people. Such training may be implemented according to themethods and under the constraints of aspects given later below in adescription of governance issues.

Outcomes of the develop stakeholders process 57 are output from thecontinuous review process 5 for inputting to the conventional RCMprocess 1. These outcomes comprise, in effect, components of a qualityplan for performing conventional RCM.

FIG. 6 is a flowchart/block diagram showing certain details of the RCMstudy process 6. The RCM study process 6 comprises various processesthat may conveniently be called as follows: a determine project scopeprocess 61, a determine hazardous operation analysis process 62, adetermine quality management structure process 63, an implement aprioritisation process 64, a develop project plan process 65, anallocate resource process 66, a develop stakeholders process 67, adetermine life cycle management process 68, and a bespoke applicationprocess 69.

The following stages of the RCM study process 6 are performed on both(i) prioritisation data and data analysis data that constitutes“baseline data” and has primarily originated from the operational issuesprocess 32 of the trigger mechanism process 3, and (ii) prioritisationdata and data analysis data derived from data that has been fed back tothe data analysis process 34 from the maintenance repair organisationprocess 8, the configuration control process 9, and the reliabilityanalysis process 12.

The determine project scope process 61 is specific to define therequirements on new RCM contract deliverables. This may result in newcommercial arrangements and contracts being developed. The project scopefor a specific RCM study may be directed to address urgent operationalrequirements or a change of role/operational context. For example amilitary aircraft operating within a hostile environment as opposed tothe home country. This may have a substantial impact of the requirementsof the preventive maintenance requirements.

Outcomes of the determine project scope process 61 are input into thedetermine hazardous operation analysis process 62.

The determine hazardous operation analysis process 62 comprisesperforming risk analysis and risk mitigation analysis. The process alsocomprises analysis of how the RCM process might fail, and how that wouldaffect the safety of the aircraft.

Outcomes of the determine hazardous operation analysis process 62 areinput into the determine quality management structure process 63.

The determine quality management structure process 63 comprisesdetermining training procedures and determining toolsets. Furtherdetails of aspects of the determination and control of trainingprocedures is given later below in a description of governance issues.Further details and examples of toolsets are also described later below.

Outcomes of the determine quality management structure process 63 areinput into the implement a prioritisation process 64.

The implement a prioritisation process 64 comprises prioritising, anddetermining details of, the program objectives. This comprises, forexample, a list of aircraft parts and respective lists of maintenanceactions that are to be taken with regard to each of those parts.

Outcomes of the implement a prioritisation process 64 are input into thedevelop project plan process 65.

The develop project plan process 65 comprises determining what has to bedone to facilitate and perform those maintenance actions, and whattimescales are relevant to them. In other words, this comprisesdetermining “what has to be done?”. Outcomes of the develop project planprocess 65 are input into the allocate resource process 66.

The allocate resource process 66 comprises allocating resources for theactivities determined in the preceding process. In other words, thiscomprises determining “how are the things that have to be done going tobe achieved?”.

Outcomes of the allocate resource process 66 are input into the developstakeholders process 67.

The develop stakeholders process 67 comprises determining which peopleor organisations will be responsible for which of the activities thathave been determined in the preceding steps. This may include trainingor relevant people. Such training may be implemented according to themethods and under the constraints of aspects given later below in adescription of governance issues.

Outcomes of the develop stakeholders process 67 are input into thedetermine life cycle management process 68.

The determine life cycle management process 68 may provide, for example,control of the RCM project using a dedicated Project Managementrepresentative to ensure the project is delivered on time, to contractand at the correct cost. The life cycle management process is anexternal quality control process that ensures the RCM study is managedfrom concept through to delivery and closure.

Outcomes of the determine life cycle management process 68 are inputinto the bespoke application process 69. This process uses any newspecific information, including information derived from data that hasbeen fed back to the data analysis process 34 from the reliabilityanalysis process 12, in response to a request for information (RFI) ore.g. in relation to a bespoke application. This will in practice usuallyoccur in tandem with contractual processes such as a standard activityknown as “launch contract”.

Outcomes of the bespoke application process 69 are output from the RCMstudy process 6 for inputting to the conventional RCM process 1. Theseoutcomes comprise, in effect, components of a quality plan forperforming conventional RCM.

FIG. 7 is a flowchart/block diagram showing certain details of theidentify preventive maintenance requirements process 7. The identifypreventive maintenance requirements process 7 comprises variousprocesses that may conveniently be called as follows: a maintenance taskanalysis process 72 and a technical authoring process 74.

The maintenance task analysis process 72 receives outcomes from theconventional RCM process 1. The outcomes may include, for example, anRCM program that specifies selected maintenance actions and schedulesfor those actions, i.e. what may be termed “what is going to be done”.The maintenance task analysis process 72 determines how the specifiedactions and schedules are going to be achieved, i.e. what may be termed“how it is going to be done”.

Outcomes of the maintenance task analysis process 72 are input to thetechnical authoring process 74.

The technical authoring process 74 is used to produce data/items such asmaintenance manuals, schedule lists and so on.

Outcomes of the technical authoring process 74 are output from theidentify preventive maintenance requirements process 7 for inputting tothe maintenance repair organisation process 8.

Additionally, outcomes of both the maintenance task analysis process 72and the technical authoring process 74 are output from the identifypreventive maintenance requirements process 7 for inputting to theconfiguration control process 11.

FIG. 8 is a flowchart/block diagram showing certain details of themaintenance repair organisation process 8. The maintenance repairorganisation process 8 comprises various processes that may convenientlybe called as follows: a fleet planning process 82, a supply chainforecasting process 84, a maintenance process 86, and an arising ratemanagement process 88.

The fleet planning process 82 receives outcomes from the identifypreventive maintenance requirements process 7, more particularly fromthe technical authoring process 74. The outcomes may include, forexample, data/items such as maintenance manuals, schedule lists and soon.

The fleet planning process 82 plans resources, facilities, spare parts,etc. For example, the received outcomes are combined with and comparedto variables such as how many aircraft are in a batch, how many servicefacilities, such as service bays, are available at the schedule timings,and so on.

Outcomes from the fleet planning process 82 are input to the supplychain forecasting process 84. Outcomes from the fleet planning process82 are also output from the maintenance repair organisation process 8for inputting to the maintenance approved organisation process 9.

The supply chain forecasting process 84 proactively determines demandforecasts, and supply/vendor management etc.

Outcomes from the supply chain forecasting process 84 are input into themaintenance process 86, i.e. provide final specification of themaintenance actions to be performed on the aircraft.

The maintenance process 86 comprises carrying out the specifiedmaintenance actions, for example maintenance actions such as replacingor testing a component of one or more aircraft.

Information and data obtained during the maintenance actions, forexample confirmation that actions have been performed, test measurementsand results, unexpected outcomes, and the like, are recorded andreported as part of the maintenance process 86, and output from themaintenance process 86 and input into the arising rate managementprocess 88.

The arising rate management process 88 analyses the data and informationreceived from the maintenance process 86 to determine and/or estimateaspects such as failure rates of components on the aircraft, how manyfailures are occurring earlier than expected or at greater than expectedlevels of occurrence, what trends can be determined, do any resultsrepresent scenarios that might be used as trigger mechanisms foranalysing/preventing further failures, and so on.

Outcomes of the arising rate management process 88 are output from themaintenance repair organisation process 8 for feeding back to thetrigger mechanism process 3, more particularly back to the data analysisprocess 34 of the trigger mechanism process 3.

FIG. 9 is a flowchart/block diagram showing certain details of themaintenance approved organisation process 9. The maintenance approvedorganisation process 9 comprises various processes that may convenientlybe called as follows: a sortie data process 92, a forward data process94, and a depth data process 96. These all use/provide examples of useof operational and maintenance feedback data.

The sortie data process 92 provides data obtained from flights by theaircraft. The data may include quantitative telemetry data and/orfeedback from pilots and/or ground crew and/or flight operators.

The forward data process 94 receives outcomes from the maintenancerepair organisation process 8, more particularly from the fleet planningprocess 82.

The forward data process 94 provides forward maintenance data, e.g. dataobtained from maintenance carried out at flight servicing or on theaircraft while in a hanger.

The depth data process 96 also receives outcomes from the maintenancerepair organisation process 8, more particularly from the fleet planningprocess 82.

The depth data process 96 provides maintenance data from components ormaterials that have been removed from the aircraft and then analysedand/or overhauled e.g. landing gear.

Outcomes from each of the sortie data process 92, the forward dataprocess 94, and the depth data process 96 are output from themaintenance approved organisation process 9 for inputting to theconfiguration control process 11 and the reliability analysis process12.

The outcomes may include, for example, maintenance and repair data,scheduled maintenance data, operator feedback or reports.

FIG. 10 is a flowchart/block diagram showing certain details of thedesign approved organisation process 10. The design approvedorganisation process 10 comprises various processes that mayconveniently be called as follows: a design fault trees process 102, asafety case process 104, a finite element analysis process 106, and astructurally significant items process 108.

The design fault trees process 102 performs bottom-up event-drivenanalysis. For example, the design fault trees process 102 takes an eventthat has occurred on the aircraft type, for example an explosion, andidentifies what systems and/or items could or would have caused thatevent. This analysis may be performed for example using mathematicalanalysis. This process may also be further informed by other processes(not shown), for example “Failure Modes and Effects CriticalityAnalysis” (FMCA).

Outcomes from the design fault trees process 102 are input into thesafety case process 104.

The safety case process 104 determines a summary or other provision ofthe risks and hazards identified in the fault trees, and determines oridentifies mitigation approaches for them. This is in effect in relationto systems of the aircraft, as opposed to structures of the aircraft.

The finite element analysis process 106 performs testing and analysis ofthe structure of the aircraft. This process may also be further informedby other processes (not shown), for example “Production Major AirframeFatigue Test” (PMAFT).

Outcomes from the finite element analysis process 106 are input into thestructurally significant items process 108.

The structurally significant items process 108 (also known as SSI)determines the structurally significant items (SSI), determines oridentifies risks and hazards associated with the structurallysignificant items, and determines or identifies mitigation approachesfor them. This is in effect in relation to the structure of theaircraft, as opposed to systems of the aircraft.

Outcomes from both the safety case process 104 and the structurallysignificant items process 108 are output from the design approvedorganisation process 10 for inputting to the configuration controlprocess 11.

The outcomes may include, for example, system safety mandatedmaintenance and structurally significant items that are important forthe continued safe operation of the aircraft systems and structuralintegrity.

FIG. 11 is a flowchart/block diagram showing certain details of theinput and output flows of the configuration control process 11.

The configuration control process 11 receives outcomes from the identifypreventive maintenance requirements process 7, the maintenance approvedorganisation process 9, and the design approved maintenance organisationprocess 10.

The configuration control process 11 performs, in effect, activitiessuch as version control, checks that the maintenance actions and plansbeing implemented correspond to those that had earlier been approved,and so on. In more detail the configuration control process 11 controlsthe input data from the maintenance and design organisations. Thisprocess primarily attempts to ensure that the data used to conduct theRCM analysis 204 is representative of the platform design andoperations. Examples of controlled input data are approved maintenancefeedback reports, faults data, operational feedback and designmodifications. The configuration control process 11 also controls theoutputs from the RCM process 204 and preventive maintenance taskanalysis process 7. This provides an audit trail and control of thepreventive maintenance schedules.

Outcomes of the configuration control process 11 are fed back to thetrigger mechanism process 3, more particularly back to the data analysisprocess 34 of the trigger mechanism process 3.

FIG. 12 is a flowchart/block diagram showing certain details of theinput and output flows of the reliability analysis process 12.

The reliability analysis process 12 receives outcomes from themaintenance approved organisation process 9.

The reliability analysis process 12 defines the continuous and actuarialreliability analysis of the platform in operation. This is in the formof monitoring faults data trigger levels, reliability trending andweibull/duane analysis, for example either on the platform, squadron orfleet.

Outcomes of the reliability analysis process 12 are fed back to thetrigger mechanism process 3, more particularly back to the data analysisprocess 34 of the trigger mechanism process 3.

The continuous RCM process 20 advantageously provides a proactivemaintenance strategy that primarily assures platform safety andreliability. It also provides a proactive maintenance that minimises therisk of unscheduled equipment failure and the subsequentoperational/maintenance effort and costs.

The following is an example of one scenario which may make use of theprocesses described above with reference to FIGS. 1 to 12.

For the purposes of this example scenario the aircraft platform will beused for the baseline RCM review process 4 and RCM analysis process 204.The hydraulics system will be used for the (proactive) continuous reviewprocess 5 and the (reactive) RCM study process 6.

The RCM analysis process 204 starts in the design and development of aplatform such as a particular military aircraft platform. A significantitem selection process 202 will be conducted on the complete aircraftplatform by system breakdown, for example the hydraulic system will havethe SIS carried out on it using the SIS algorithms defined in the RCMstandards such as “Procedures for Developing PreventiveMaintenance—AP100C-22” and “Operator/Manufacturer Scheduled MaintenanceDevelopment—MSG-3”. Each and every system on the aircraft will have theSIS process 202 carried out using design source data such as, safetycase analysis, system functional descriptions, engineering drawings andinterfaces.

On completion of the SIS process 202, a descriptive candidate itemclassification will have been applied to each item within the system.For example, within the hydraulics system candidates may be classifiedas either zonal process 206, functionally significant items (FSI)process 208 or structurally significant items (SSI) process 210.

The bespoke application of RCM will then be applied in accordance withthe standards such as “Procedures for Developing PreventiveMaintenance—AP100C-22” reports and “Operator/Manufacturer ScheduledMaintenance Development—MSG-3”. The zonal analysis process 206 will beapplied to zonal candidates, rating each zone dependant onsusceptibility to accidental and environmental factors which may inducea multiple failure scenario.

The FSI analysis process 208 will be applied to candidates with afunctional significance; this includes performing a failure modes andeffects analysis and determining a theoretical criticality of loss offunction. The RCM algorithm is then performed on the candidate“in-accordance-with” standards such as, “Procedures for DevelopingPreventive Maintenance—AP100C-22” reports and “Operator/ManufacturerScheduled Maintenance Development—MSG-3”.

The SSI analysis process 210 will be applied to candidates with astructural significance; this includes rating the structure forenvironmental and accidental structural rating factors and performing afailure modes and effects analysis and determining a theoreticalcriticality of loss of function. The RCM algorithm is then performed onthe candidate in-accordance-with standards such as “Procedures forDeveloping Preventive Maintenance—AP100C-22” reports and“Operator/Manufacturer Scheduled Maintenance Development—MSG-3”.

The completed system analysis may then quality assured using agovernance process such as the governance and maintenance process 500described later below with reference to FIG. 14, including consequentialgovernance procedures and audit processes derived thereby. The auditsare conducted in hierarchical phases. The first is performed by the RCMauditor for RCM logic and analysis process validity against the contractstandards such as “Procedures for Developing PreventiveMaintenance—AP100C-22” reports and “Operator/Manufacturer ScheduledMaintenance Development—MSG-3”. The second phase of audit is performedby the designed approved authority for technical validity; the finalphase of audit is by the operator approved authority for operationalvalidity.

The detailed analysis and approvals of the system analysis for examplethe hydraulics system will be conducted in a formal maintenance workinggroup process 214. The detailed RCM analysis supporting the preventivemaintenance recommendations will be reviewed and all responses recordedbefore approval of the maintenance programme.

The approved hydraulics system preventive maintenance tasks from themaintenance working group process 214 will be reviewed for operationaland type certification impact before approval at the maintenance reviewboard process 216.

The approved preventive maintenance tasks undergo supportabilityanalysis to define the preventive maintenance requirements process 7such as, facility, spares, support equipment and detailed proceduralrequirements.

The detailed preventive maintenance requirements for the hydraulicssystem process 7 will be technically authored into maintenancepublications and recorded against a released publication version in theconfiguration control process 11 before release into the maintenanceapproved organisation process 9 for use on the aircraft.

Feedback data from the hydraulics system such as component replacements,maintenance actions, and defect investigations will be recorded againstthe maintenance work orders at forwards operations process 94. Any itemsthat are sent back to industry or for specialist repair will be recordedon the depth maintenance system process 96 for fault and rectificationaction. The operators such as pilots and aircraft preparation crew willprovide any operational faults, warnings or query feedback through anoperational data system process (e.g. sortie data process 92). This mayalso include telemetry and downloaded data from the aircraft systems.Reliability analysis process 12 is applied against a trended andcleansed form of the maintenance approved organisation data process 9.The reliability analysis provides actuarial monitoring of trends againstthe hydraulics system and components performing within or outside oftheir design performance characteristics and theoretical inherentreliability.

The approved maintenance schedule publications from 7 are used by themaintenance and repair organisation process 8 to plan fleet maintenanceactivities and a facility/resource requirements process (e.g. fleetplanning process 82). The supply chain also use the preventivemaintenance parts forecast to define a proactive supply chain demandagainst planned periods of maintenance activity (i.e. this is the supplychain forecasting process 84). The subsequent preventive maintenanceactions, unscheduled maintenance actions process 86 and the level ofparts replenishments are continually monitored against a forecast rateusing arising rate management process 88.

The baseline RCM derived preventive maintenance from process 204 iscontinually informed from the outputs from the maintenance repairorganisation process 8 for fleet planning process 82, supply chaindemands process 84 and arising rate management process 88. This triggersthe trigger mechanism process 3, with a subsequent review of the RCManalysis using the actual results from supply chain and maintenanceplanning activities. The actual reliability results from the reliabilityanalysis process 12 and from sortie data process 92 and maintenancefeedback processes (i.e. forward data process 94 and depth data process96) provides feedback on the performance of the hydraulics system andcomponents to the maintenance steering group process 38, whereby aprioritisation on the hydraulics components and sub-systems is definedusing the maintenance repair organisation process 8, the maintenanceapproved organisation process 9, the design approved organisationprocess 10 and the reliability analysis (i.e. reliability data) process12.

The RCM analysis process is managed continually for improvement by themaintenance and operational requirements determined in the maintenancesteering group process 38. Another RCM baseline review can be applied tothe entire hydraulics system using the baseline review process 4. Thistends to be a costly and time consuming exercise that is generallyapplicable to the initial design and development review discussedearlier in this section. In conducting a baseline review a project andcontext scope is carried out (e.g. using the determine project scopeprocess 41) to determine the detailed baseline review requirements, thisbeing done in accordance with the governance process mentioned aboveearlier in this description of an example scenario.

The scope will define the stakeholders, business processes, resourcesand information systems required to conduct the baseline review on, forexample, either the full aircraft suite of systems or a specific systemsuch as the hydraulics system. A hazardous operations analysis process42 is conducted on the project scope which identifies the risks andmitigations in conducting the baseline review. This will identify suchthings as stakeholder involvement and information system impact on theaircraft operation resulting in low quality hydraulics analysis. Aquality management structure process 43 is then defined and implementfor the baseline review with an identified organisational reportingstructure against trained and competent analysts. The quality managementstructure process 43 and hazardous operation analysis process 42 aredone in accordance with the governance process mentioned above earlierin this description of an example scenario.

The implementation of the quality management structure is planned in theimplement a prioritisation process 44 and a project plan for theimplementation and baseline review is developed in the develop projectplan process 45. The develop project plan process 45 identifies theresource to perform the baseline review process 4 and the allocateresource process 46 allocates physical resources to the tasks within thedevelop project plan process 45. The allocated resources from process 46are positioned into pre-determined roles and are used to develop thewider stakeholders in the develop stakeholders process 47 to support andapprove the RCM analysis process 204. The stakeholders are typicallydesign, technical, operational, engineering and aircraft authorities whorequire an input into the analysis process 204 from the design process10, reliability analysis process 12, maintenance organisation process 9and maintenance repair organisation process 8. The stakeholders alsoprovide the validation within the quality assurance process 212,maintenance working group process 214 and maintenance review boardprocess 216.

A continuous review process 5 on a proactive basis can be applied to thesystem dependent on a level of operational/design change criteria. Thisgenerally would be applied if the hydraulics system was performingadequately and no single cause of maintenance impact can be determined;i.e. it could be an accumulation of components in the system, filters,flow valves and valve blocks attributing the faults within thehydraulics system. In conducting a continuous review a project andcontext scope is carried out on the system in question, for example thehydraulics system in process 51. This scope provides a summary ofcontinuous review requirements; this is done in accordance with thegovernance process mentioned above earlier in this description of anexample scenario.

The scope will define the stakeholders, business processes, resourcesand information systems required to conduct the continuous review on,for example, the hydraulics system. An update to the baseline reviewhazardous operations analysis process 42 is conducted for the hydraulicssystem in process 52 which identifies the risks and mitigations inconducting the continuous hydraulics system review. This will identifysuch things as stakeholder involvement and information system impact onthe aircraft operation resulting in low quality hydraulics analysis. Thequality management structure from process 43 is reviewed in process 53against the requirements for the continuous review project scope process51. The quality management structure process 53 and hazardous operationanalysis process 52 are done in accordance with the governance processmentioned above earlier in this description of an example scenario.

The implementation of the quality management structure is planned in theimplement a prioritisation process 54 and a project plan for theimplementation and the continuous review is developed in the developproject plan process 55. The develop project plan process 55 identifiesthe resource to perform the hydraulics system review process 5 and theallocate resource process 56 allocates physical resources to the taskswithin the develop project plan process 55. The allocated resources fromprocess 56 are positioned into pre-determined roles and are used todevelop the wider stakeholders in the develop stakeholders process 57 tosupport and approve the RCM analysis process 204. The stakeholders aretypically design, technical, operational, engineering and aircraftauthorities who require an input into the analysis process 204 from thedesign process 10, reliability analysis process 12, maintenanceorganisation process 9 and maintenance repair organisation process 8.The stakeholders also provide the validation within the qualityassurance process 212, maintenance working group process 214 andmaintenance review board process 216. The RCM analysis process 204 isthen re-run in accordance with the project scope process 51, hazardousoperations analysis process 52, quality management structure process 53,and develop project plan process 55.

An RCM study 6 can be performed on a reactive basis on selectedcomponents within the hydraulics system that are being identified usingthe maintenance repair organisation process 8, the maintenance approvedorganisation process 9, the design approved organisation process 10 andthe reliability analysis (reliability data) process 12. An RCM study canalso be initiated if the system has been identified as being subject tooperational environmental changes. For example, if the hydraulics systemperformed differently due to operations in hostile operational orenvironmental circumstances. In conducting a continuous review a projectand context scope is carried out on the system in question, for examplethe hydraulics system in the determine project scope process 61. Thisscope provides a summary of RCM review requirements; this is done inaccordance with the governance process mentioned above earlier in thisdescription of an example scenario.

The scope will define the stakeholders, business processes, resourcesand information systems required to conduct the RCM review on, forexample, the hydraulic valve block. An update to the baseline reviewhazardous operations analysis process 42 is conducted for the hydraulicvalve block in process 62 which identifies the risks and mitigations inconducting the hydraulic valve block review. This will identify suchthings as stakeholder involvement and information system impact on theaircraft operation resulting in low quality hydraulics analysis. Thequality management structure from process 43 is reviewed in process 63against the requirements for the continuous review project scope process61. The quality management structure process 63 and hazardous operationanalysis 62 are done in accordance with the governance process mentionedabove earlier in this description of an example scenario.

The implementation of the quality management structure is planned in theimplement a prioritisation process 64 and a project plan for theimplementation and the RCM review is developed in the develop projectplan process 65. The develop project plan process 65 identifies theresource to perform the hydraulic valve block review process 6 andprocess 66 allocates physical resources to the tasks within the projectplan process 65. The allocated resources from process 66 are positionedinto pre-determined roles and are used to develop the wider stakeholdersin process 67 to support and approve the RCM analysis process 204. Thestakeholders are typically design, technical, operational, engineeringand aircraft authorities who require an input into the analysis process204 from the design process 10, reliability analysis process 12,maintenance organisation process 9 and maintenance repair organisationprocess 8. The stakeholders also provide the validation within thequality assurance process 212, maintenance working group process 214 andmaintenance review board process 216.

If the project scope requirements in process 61 determine a fulloperational context review of the hydraulics system or a number ofaffected systems, then a life cycle management framework is implementedin the determine life cycle management process 68. This would apply to,for example, a study into the operation of the hydraulics system of theparticular type of military aircraft within a given environmentallyhostile operational area. The determine life cycle management process 68identifies a number of project management gates in which the RCM reviewmay be audited against for progress, expended technical resource, andcost in performing the analysis. This is managed by a dedicated projectmanager and reported back to both the commercial, aircraft and designauthorities. As a result a bespoke and tailored preventive maintenancereport is developed in the bespoke application (of RCM) process 69 thatidentifies the bespoke preventive maintenance requirements on, forexample, the hydraulics system whilst the aircraft is operating withinthe given environmentally hostile operational area. This bespokeapplication (of RCM) process 69 is then used to conduct the RCM analysisprocess 204.

FIG. 13 is a block diagram of a control process 300 for controllingaspects of the above described embodiments, and any other embodimentsdescribed later below, of the continuous RCM process 20. The controlprocess may conveniently be implemented in the form of software forproviding control outputs. This software, or other forms ofimplementation of the control process 300, may be considered as a formof toolset in the sense that this term is used sometimes in the field ofRCM.

Accordingly, the following description of the control process 300 mayallow even more detailed understanding of the above describedembodiments of the continuous RCM process 20, or at least certain partsof, or examples of, those embodiments of the continuous RCM process 20.Indeed, one or more advantageous aspects of the control process 300provide additional elements to yet further embodiments extending therebyfrom the above described embodiments of the continuous RCM process 20.However, in the opposite sense, it is also noted that the followingexample(s) of the control process 300 include further control detailsthat in themselves may tend to be advantageous and that are notessential for the implementation of many embodiments of the continuousRCM process 20.

The control process 300 comprises the following elements that are inessence performed in the following sequence: a significant itemselection (SIS) element 302, a failure modes and effects analysis (FMEA)element 304, an algorithm element 306, a tasks element 308, a samplingelement 310, a reports element 312 and an audit element 314. FIG. 13also represents in effect a data flow route i.e. from the significantitem selection (SIS) element 302 to the failure modes and effectsanalysis (FMEA) element 304 to the algorithm element 306 to the taskselement 308 to the sampling element 310 to the reports element 312 andfinally to the audit element 314. In other examples of the controlprocess 300, one or more of these elements may be omitted.

The format of FIG. 13 is such that the following elements laid out inFIG. 13 in columns related to certain of the elements described above inthe preceding paragraph represent in effect possibilities of what may beproduced by the respective element described above in the precedingparagraph, as follows.

In the case of the SIS element 302: reference data 316, and progressdata 318. These elements provide the archive of the originalreference/source data that has been/will be used for the RCM analysisprocess 204. The reference data 316 is provided via the configurationcontrol process 11. The SIS element is the down selection of preventivemaintenance candidates for RCM analysis using the reference data element316. The progress data 318 is the project management timescalesrequirement for the RCM analysis process 204; this provides continualmonitoring of RCM analysis against an agreed project schedule.

In the case of the algorithm element 306: validation data 319, zone RCMalgorithm data 320, FSI RCM algorithm data 322, and SSI RCM algorithmdata 324. The algorithmic development of the FSI, SSI and zonal RCManalysis is undertaken in accordance with the contractual RCM standards.Examples of these standards and algorithms are contained in“Operator/Manufacturer Scheduled Maintenance Development—MSG-3” and“Procedures for Developing Preventive Maintenance—AP100C-22”.

In the case of the reports element 312: PM1 data 326, PM2 a data 328,PM2 b data 330, PM4 data 332, PM5 data 334, benchmarking data 335, EZAPdata 336, progress reports data 338, and users data 340. These reportsare similar in content: the PM1 data 326 comprises item details; the PM2a data 328 comprises a lifed items list; the PM2 b data 330 comprisesfailure modes and effects criticality analysis and RCM algorithms, thePM4 data 332 comprises zonal analysis data; the PM5 data 334 comprisessampling analysis data; the EZAP data 336 comprises enhanced zonalanalysis data. The PM reports, e.g. the progress reports 338 arestandard “Procedures for Developing Preventive Maintenance—AP100C-22”reports. The EZAP data 336 is an addition from “Operator/ManufacturerScheduled Maintenance Development—MSG-3”. A new type of report isprovided using benchmarking data 335, as well as for example comparativemaintenance programme analysis at a pre and post RCM review stage atplatform, system, sub-system or component level. The progress reportsdata 338 defines the project schedule adherence and RCM analysisprogress against the process 204. User data (reports data) 340 comprisesuser defined outputs that can be tailored by the user on an ad hocbasis.

In the case of the audit element 314: in-work data 342, forum data 344,and archive data 346. These types of data provide workflow management ofthe RCM process 204. The audit element 314 provides records of completedand approved RCM analysis reports. In-work data element 342 allowseditable RCM analysis in draft form to be released for comments; thesecomments are recorded in a discussion forum element 344. Once amaintenance working group process 214 has been completed on the basis ofthe comments from the forum element 344 the RCM analysis reports can befinalised and approved as read only records in the archive element 346.

In this example, the SIS element 302 corresponds to the significant itemselection process 202 of the conventional RCM process 1 part of theearlier described continuous RCM process 20.

In this example, the SIS element 302 provides reference data 316.Provision of this reference data 316 by the SIS element 302 makes use ofinput from design approved organisation functionality 350. The designapproved organisation functionality 350 comprises fault tree analysisfunctionality 352, safety case functionality 354, finite elementanalysis functionality 356, and structurally significant items (SSI)functionality 358. The fault tree analysis functionality 352 is arrangedto feed data in to the safety case functionality 354. The finite elementanalysis functionality 356 is arranged to feed data in to thestructurally significant items (SSI) functionality 358. The safety casefunctionality 354 and the structurally significant items functionality358 are arranged to feed data in to the SIS element 302. The designapproved organisation functionality 350, and its constituentfunctionalities, correspond to, and operate with the same effect as, thecorresponding processes of the design approved organisation process 10that forms part of the example of a continuous RCM process 20 describedearlier above.

In this example, the SIS element 302 also provides progress data 318.This progress data 318 is data for managing and tracking projectperformance, e.g. start and finish dates.

In this example, the SIS element 302 receives input from LSARfunctionality 360. The LSAR 360 provides a logistical support analysisrecord (i.e. source/input data). The LSAR 360 has maintenance andsupport requirements i.e. may be viewed as a configurationmaster-source. The output of the LSAR 360 provides a direct interfaceinto the list of candidates for the SIS element 302 at the start of theRCM analysis process 204.

In this example, the FMEA element 304 provides failure modes and effectsanalysis. The FMEA element 302 makes use of input from maintenanceapproved organisation functionality 370. The maintenance approvedorganisation functionality 370 comprises sortie data functionality 372,forward maintenance functionality 374, and depth maintenancefunctionality 376. The maintenance approved organisation functionality370, and its constituent functionalities, correspond to, and operatewith the same effect as, the corresponding processes of the maintenanceapproved organisation process 9 that forms part of the example of acontinuous RCM process 20 described earlier above.

In this example, the algorithm element 306 provides appropriatealgorithm types for later use. The algorithm types include zone RCMalgorithms 320, FSI RCM algorithms 322 and SSI RCM algorithms 324. Ineach case, a plurality of different versions of each type of algorithmare provided, e.g. one for each type of aircraft that the controlprocess 300 and/or the continuous RCM process 20 is to be used for.Shown by way of example in FIG. 13 are three different versions 320 a,320 b, and 320 c of zone RCM algorithms, three different versions 322 a,322 b, and 322 c of FSI RCM algorithms, and three different versions 324a, 324 b, and 324 c of SSI RCM algorithms. This is the application ofthe algorithms within the contractual RCM standards, such as “Proceduresfor Developing Preventive Maintenance—AP100C-22” reports, and“Operator/Manufacturer Scheduled Maintenance Development—MSG-3”.

In this example, the algorithm element 306 also provides validation data319. The background to this validation data is that operators or systemsmay inadvertently extend outside of the appropriate rules being used in,for example, the continuous RCM process 20. The validation data 319 isused for automatic data validation. An output may be provided to agraphical user interface (GUI) for showing conformity or contraventionof the rules.

In this example, the tasks element 308 provides an analogous role to aconventional RCM process of defining what is going to be done, forexample defining preventive maintenance tasks. This may includeidentifying whether a given preventive maintenance task is driven bysafety case considerations/outputs or by structurally significant items(SSI) considerations/outputs.

In this example, the sampling element 310 provides functionality toperform RCM derived sampling. Sampling is used to validate preventivemaintenance tasks by requesting instruction for feedback on theeffectiveness and findings from conducting the preventive maintenancetask.

In this example, the reports element 312 provides data that correspondsto various reports and the like, as follows. The PM1 data 326—itemdetails. The PM2 a data 328—lifed items list. The PM2 b data 330—failuremodes and effects criticality analysis and RCM algorithms. The PM4 data332—zonal analysis. The PM5 data 334—sampling analysis. The EZAP data336—enhanced zonal analysis. The PM reports are in the contractual RCMstandards such as “Procedures for Developing PreventiveMaintenance—AP100C-22” reports. The EZAP is an addition from“Operator/Manufacturer Scheduled Maintenance Development—MSG-3”.Additional reports have been developed to provide benchmarking data 335comparative maintenance programme analysis at a pre and post RCM reviewstage at platform, system, sub-system or component level. Progressreports data 338 defines the project schedule adherence and RCM analysisprogress against the RCM analysis process 204. User data (reports data)340 comprises user defined outputs that can be tailored by the user onan ad hoc basis.

In this example, the reports element 312 provides, as mentioned above,PM1 data 326, PM2 a data 328, PM2 b data 330, PM4 data 332, PM5 data334, benchmarking data 335, EZAP data 336, progress reports data 338,and users data 340.

Provision of the PM1 data 326 by the reports element 312 makes use ofinput from the SIS element 302. The PM reference of the report isderived from “Procedures for Developing PreventiveMaintenance—AP100C-22”. The PM1 in its generic form is the item detailsreport containing the descriptive nomenclature data, assembly andreliability of the item under analysis.

Provision of the PM2 a data 328 by the reports element 312 makes use ofinput from the algorithm element 306, more particularly from one or moreof the algorithms 320, 322, 324. The PM reference of the report isderived from “Procedures for Developing PreventiveMaintenance—AP100C-22”. The PM2 a in its generic form is the componentlife data that relates to the item overhaul, replacement and restorationdetails.

Provision of the PM2 b data 330 by the reports element 312 makes use ofinput from the algorithm element 306, more particularly from one or moreof the algorithms 320, 322, 324. The PM reference of the report isderived from “Procedures for Developing PreventiveMaintenance—AP100C-22”. The PM2 b in its generic form is the Failuremodes and effects analysis and RCM algorithm results.

Provision of the PM4 data 332 by the reports element 312 makes use ofinput from the algorithm element 306, more particularly from one or moreof the algorithms 320, 322, 324. The PM reference of the report isderived from “Procedures for Developing PreventiveMaintenance—AP100C-22”. The PM4 in its generic form is the zonalanalysis report defining the ratings of accidental and environmentalzonal rating factors.

Provision of the PM5 data 334 by the reports element 312 makes use ofinput from the sampling element 310. The PM reference of the report isderived from “Procedures for Developing PreventiveMaintenance—AP100C-22”. The PM5 in its generic form is the definition ofa sampling requirement such as information requirements, task detailrequirements and a range of the sample population at either the (forexample) item, platform, squadron or fleet.

Each type of the PM data, i.e. the PM reports, namely the PM1 data 326,the PM2 a data 328, the PM2 b data 330, the PM4 data 332, and the PM5data 334, is a respective conventional PM report as defined/used inconventional RCM, for example in conventional RCM performed according to“Operator/Manufacturer Scheduled Maintenance Development—MSG-3”.

Provision of the benchmarking data 335 by the reports element 312 makesuse of input from the tasks element 308.

The benchmarking data 335 is used, for example, to benchmark currentversions or implementations of the maintenance programs compared toprevious versions, to determine what has changed as the continuous RCMprocess, for example, has been modified over time.

Provision of the EZAP data 336 by the reports element 312 (where “EZAP”is Enhanced Zonal Analysis Procedure) makes use of input from thealgorithm element 306, more particularly from one or more of thealgorithms 320, 322, 324.

The EZAP data 336 is used, for example, to assess or indicate zonalsafety hazards. The PM reference of the report is derived from“Operator/Manufacturer Scheduled Maintenance Development—MSG-3”. TheEZAP in its generic form is the zonal analysis of safety related hazardsdue to multiple failure, such as combustible materials, deterioration inwiring, ignition sources, lightning protection or exposure to highintensity radio frequency.

Provision of the progress reports data 338 by the reports element 312makes use of input from the SIS element 302, more particularly theprogress data 318 described earlier above, i.e. data for managing andtracking project performance, e.g. start and finish dates.

Accordingly the progress reports data 338 is used, for example, tomanage and track project performance, e.g. start and finish dates.

The users data 340 provides a report facility to provide reports tousers of, for example, the continuous RCM process 20. More particularly,in this example, this functionality provides a user defined reportfacility on an ad hoc basis.

In this example, the audit element 314 provides data archiving and workflow control/management. For example, the audit element 314 providesin-work data 342, forum data 344, and archive data 346. The in-work data342 is provided for assessment/discussion/approval by stakeholders. Theforum data 344 provides a form of distribution list. The in-work data342 may be fed in to the forum data 344. The archive data 346 provides astore of data that is stored in a non-changeable form, e.g. as oftenknown as “read-only”. The forum data may be fed in to the archive data346. Read-out or other output of/from the archive data 346, may, forexample and as shown in FIG. 13, comprise in effect outputting orfeeding the archive data 346 to additional LSAR functionality 382 and toconfiguration data functionality 384.

The configuration data functionality 384 is in effect providing exportor outputting of configuration data corresponding to configuration dataprovided by/described with reference to the configuration controlprocess 11 that forms part of the example of a continuous RCM process 20described earlier above (in particular the aspects of a baseline RCMreview and a controlled continuous improvement or RCM process).

The additional LSAR functionality 382 is an interface between, on theone side, the RCM analysis process 204 and toolset outputs element (i.e.archive data element 346), and, on the other side a maintenance andsupportability analysis information system based upon the requirementsof standards such as Application of Integrated Logistics Support DEFSTAN 00-60 and 00-600.

Data provided by from the additional LSAR functionality 382 is output totechnical authoring functionality 386 and to fleet planningfunctionality 388. This may, advantageously, be implementedautomatically in response to a simple input instruction, such as aclick, by a human operator via a GUI.

The technical authoring functionality 386 corresponds to, and operateswith the same effect as, the corresponding technical authoring process74 of the identify preventive maintenance requirements process 7 thatforms part of the example of a continuous RCM process 20 describedearlier above.

Data provided by the fleet planning functionality 388 is output toforward maintenance functionality 390 and to depth maintenancefunctionality 392. The fleet planning functionality 388, forwardmaintenance functionality 390, and depth maintenance functionality 392correspond to, and operate individually and in combination with the sameeffects as, the following respective corresponding processes that formparts of the example of a continuous RCM process 20 described earlierabove: the fleet planning process 82, the forward data process 94, andthe depth data process 96.

The control process 300 tends to provide the following advantages:autonomous control of the RCM business process 204; and autonomousassurance and validation against RCM standards (such as “Procedures forDeveloping Preventive Maintenance—AP100C-22” reports and“Operator/Manufacturer Scheduled Maintenance Development—MSG-3”).Furthermore, the control process 300 provides workflow management andinterrogation of input and output data sources from a configurationcontrolled and approved maintenance programme. The control process 300provides governance, assurance and a performance enhancing method thatallows simplified and effective forms of these, despite the extremelycomplex nature of the RCM analysis process 204 and the overallcontinuous RCM process 20.

FIG. 14 is a process flowchart showing certain steps of an example of anRCM governance and maintenance actions process 500 that may optionallybe applied, for example, to the above described embodiments of thecontinuous RCM process 20.

At step 502, a military aircraft governance framework is provided, forexample by formalising an approach based on guidance given within “UsingReliability Centred Maintenance to Manage Engineering Failures” DEF STAN0-45, “Maintenance Approved Organisation Scheme” DEF STAN 05-130 and“Operator/Manufacturer Scheduled Maintenance Development—MSG-3”.

At step 504, a civil aircraft governance framework 504 is provided, forexample, a governance regime as specified and regulated by the UK CivilAviation Authority (CAA) “Airworthiness Procedures where the CAA hasPrimary Responsibility for Type Approval of the Produce”—CAP553 and/orthe Federal Aviation Administration in the USA (FAA) order “AircraftCertification Governance” 1370.76B.

It is noted that steps 502 and 504 are shown in FIG. 14 as taking placein parallel. They may however alternatively be performed sequentially,or in some form of partial temporal overlap.

At step 506, some or all of the civil aircraft governance framework iscompared to some or all of the military aircraft governance framework.

At step 508, one or more components of the civil aircraft governanceframework is added to, i.e. incorporated in, the military aircraftgovernance framework to provide a modified military aircraft governanceframework.

At step 510, RCM is performed on a military aircraft, including theresulting performance of maintenance actions, such as replacing ortesting a component of the aircraft, under the control and supervisionof the modified military aircraft governance framework. In this example,the RCM that is performed, and the resulting maintenance actions, arethe continuous RCM process 20 as described earlier above. However, inother examples, they may be any other appropriate military aircraft RCMprocess, including for example a stand-alone version of the conventionalRCM process 1 described earlier above.

In this example, the governance framework comprises the military andcivil guidance for conducting RCM “Using Reliability Centred Maintenanceto Manage Engineering Failures” DEF STAN 0-45, “Maintenance ApprovedOrganisation Scheme” DEF STAN 05-130 and “Operator/ManufacturerScheduled Maintenance Development—MSG-3”; and in particular:

-   -   Organisation process framework (within the Integrated Solutions        Business Model).    -   Project specific Quality Management System frameworks or Policy        and Procedures Handbooks (PPH).    -   RCM Training course framework for practitioners, SMEs and        stakeholders.    -   RCM Maintenance Working Groups (MWG) for approval of RCM        analysis.

In further examples, plural civil aircraft governance frameworks may bemade use of in parallel as part of steps 504, 506, and 508, rather thanjust one civil aircraft governance framework.

In yet further examples, plural military aircraft governance frameworksmay be modified or combined as part of steps 502, 506, and 508, inaddition to incorporating one or more components from one or more civilaircraft governance frameworks.

In yet further examples, any of the above examples may further includesteps of providing one or more governance frameworks from other areas ofindustry (other than military or civil aircraft), and as part of step506 additionally comparing that or those to the provided militaryaircraft governance framework, and accordingly at step 508 additionallyincorporating one or more components of the governance frameworks fromother areas of industry to provide the modified military aircraftgovernance framework that is then used in step 510. Examples of theother areas of industry are oil, gas, and nuclear power.

Thus, in overview, the present inventor has extracted techniques fromcivil aerospace governance approaches and other industrial governanceapproaches and applied them to military aerospace governance of RCM.

For example, some examples of techniques that have been extracted are asfollows:

-   -   Trained RCM analysts.    -   Trained RCM Assurance Leaders.    -   Trained Stakeholders.    -   Central governance and certification function.    -   Central Maintenance Programme Review function.    -   Approved and validated RCM methodologies.    -   End to End Project scope and implementation framework.    -   Hazardous operational analysis and risk mitigation.    -   Detailed Military Aircraft Structural RCM analysis method.    -   Detailed Civilian Aircraft Enhanced Zonal Analysis Procedures.

Any one or more of the above may be extracted in different respectiveexamples.

Accordingly, various techniques are made use of that have, over thecourse of time, been improved more in the field of civil aircraft RCMgovernance, or made more uniform (and when also incorporated, RCMgovernance in other areas of industry) compared to corresponding lesserimprovements in the field of military aircraft RCM governance. Thus, inthe above examples, the benefits of these more-developed techniques areadvantageously made use of in the field of military aircraft RCMgovernance. This is the result, at least in part, of the presentinventor breaking through a long-held technical prejudice in the fieldof military aircraft RCM governance that the fundamental differencesbetween military aircraft RCM governance and civil aircraft RCMgovernance (and also RCM governance of other areas of industry) set themsufficiently far apart in their characteristics that components of oneare not applicable to the other. Thus, in essence, the present inventorhas made the surprising realisation, against the above mentionedlong-held technical prejudice, that even though there is a significantsize of the fundamental differences between military aircraft RCMgovernance and civil aircraft RCM governance (and also RCM governance ofother areas of industry), nevertheless because improvements made in thefield of civil aircraft RCM governance (and also RCM governance of otherareas of industry) have tended to be significantly greater over timethan those made in the field of military aircraft RCM governance, thenit is now of benefit to incorporate current civil aircraft (and otherindustry areas) improvements in military aircraft RCM governance as thesize of the improvements of these now outweigh the significant size ofthe fundamental differences between military aircraft RCM governance andcivil aircraft RCM governance (and also RCM governance of other areas ofindustry).

The above described RCM governance comprises activities such asmaintaining the RCM process within defined bounds, and is achieved atleast in part by performing processes such as those described above asforming part of the baseline review process 4, for example set-up typeprocesses. This may include processes such as the develop stakeholdersprocess 47 described earlier above. For example, for a given platform,for example type of aircraft, a respective team leader and respectivequality assurance controllers may be provided at the top of ahierarchical operator arrangement. Such a team leader may, for example,control or manage the setting-up processes of the baseline reviewprocess 4, and the more ongoing processes of the continuous reviewprocess 5, the RCM study process 6, and the conventional RCP process 1when part of the continuous RCM process 20. Such a quality assurancecontroller may, for example, control or manage quality assuringprocesses that process outputs from the conventional RCM process 1 whenpart of the continuous RCM process 20. Below the team leader and qualityassurance controller may be a hierarchy of operators for monitoring andprocessing the RCM processes and for assuring the processes andoutcomes. Respective team leaders from respective platforms take placein common control/management processes whereby individual insight istaken advantage of collectively, in a structured and programmed mannerin which large amount of detail are processed in a structured andprogrammed manner. It will be appreciated by the person skilled in theart RCM governance that both RCM and RCM governance are highly complexprocesses, and the full detailed specification of any specific RCMprogram/governance program would in practice usually require manythousands of pages or data sets. Accordingly the description here is bynecessity in a simplified form. The person skilled in the art of RCMgovernance will be aware of this and will accordingly be able toimplement highly complex systems/processes/programs based on thesesimplified descriptions, as this by necessity is a skill routinelyemployed in this field.

Apparatus, for implementing part or all of each of the abovearrangements including respective functional modules/elements, andperforming the respective method steps/process steps/elements/data flowsetc., may be provided by configuring or adapting any suitable apparatus,for example one or more computers or other processing apparatus orprocessors, and/or providing additional modules. The apparatus maycomprise a computer, a network of computers, or one or more processors,for implementing instructions and using data, including instructions anddata in the form of a computer program or plurality of computer programsstored in or on a machine readable storage medium such as computermemory, a computer disk, ROM, PROM etc., or any combination of these orother storage media.

It will be appreciated that the above described embodiments are merelyparticular implementation examples that are possible from a large numberof examples of very complex arrangements. Accordingly, in furtherembodiments any one or more process step/functional module/dataflow/data element etc. may be omitted, or its respective position orinteraction rearranged, unless stated otherwise above. This is the casefor both the hierarchical level shown in FIG. 2 for components of thecontinuous RCM process 20 (i.e. for the inclusion of, and/or relativerelationship between, processes such as the trigger mechanism process 3,the baseline review 4, and so on) and for the hierarchical level shownin FIG. 1 and FIGS. 3-12 (i.e. for the inclusion of, and/or relativerelationship between, the component processes that go together to form arespective process from amongst the processes such as the triggermechanism process 3, the baseline review 4, and so on) and the differentcomponent parts shown in FIGS. 13 and 14.

Furthermore, in relation to any of the above described embodiments, inyet further embodiments one or more additional process steps/functionalmodules/data flows/data elements etc. may be included in addition to theones described above, i.e. may be inserted between the ones describedabove, and will accordingly therefore change certain details of wheredata flows in terms of from one process step/functional module/dataflow/data element etc. to another.

The above described embodiments relate to RCM specifically for militaryaircraft, but this need not be the case, and in other embodiments thecontinuous RCM process may be applied to or adapted for other types ofaircraft or vehicles, or indeed other complex or safety criticalsystems.

What is claimed is:
 1. A maintenance method based on reliability centredmaintenance (RCM), the maintenance method comprising: performing RCM,producing RCM outcomes; feeding the RCM outcomes to an identifypreventive maintenance requirements process, producing identifypreventive maintenance requirements process outcomes; feeding theidentify preventive maintenance requirements process outcomes to amaintenance repair organisation process, producing maintenance repairorganisation process outcomes; feeding the maintenance repairorganisation process outcomes to a maintenance approved organisationprocess and an update process, the update process comprising a triggermechanism process; a baseline review process; a continuous reviewprocess; an RCM study process, wherein the trigger mechanism processreceives input from the maintenance repair organisation process andprovides input to the baseline review process, the continuous reviewprocess, and the RCM study process; performing the update process toprovide update data for performing the RCM; and inputting the updatedata into the performing of the RCM.
 2. A method according to claim 1,comprising: carrying out a maintenance action selected by the performingof the RCM; and wherein the outcomes derived from performing the RCMthat are fed to the update process comprise outcomes from themaintenance action that is carried out.
 3. A method according to claim2, wherein the carried out maintenance action is performed as part ofthe maintenance repair organisation process.
 4. A method according toclaim 1, comprising: carrying out a maintenance action performed at atime specified by the performing of the RCM, and wherein the outcomesderived from performing the RCM that are fed to the update processcomprise outcomes from the maintenance action that is carried out.
 5. Amethod according to claim 1, comprising: carrying out a maintenanceaction performed to an extent specified by the performing of the RCM,wherein the outcomes derived from performing the RCM that are fed to theupdate process comprise outcomes from the maintenance action that iscarried out.
 6. A method according to claim 1, comprising: acontinuously updating RCM process.
 7. A method according to claim 1,wherein the maintenance method is applied to a military aircraft. 8.Apparatus for performing a maintenance method based on reliabilitycentred maintenance (RCM), the apparatus comprising: one or moreprocessors configured to perform the following function in a feedbackmanner: i) performing RCM, producing RCM outcomes; ii) feeding outcomesderived from performing the RCM to an identify preventive maintenancerequirements process, producing identify preventive maintenancerequirements process outcomes; iii) feeding the identify preventivemaintenance requirements process outcomes to a maintenance repairorganisation process, producing maintenance repair organisation processoutcomes; iv) feeding the maintenance repair organisation processoutcomes to a maintenance approved organisation process and an updateprocess, the update process comprising a trigger mechanism process; abaseline review process; a continuous review process; an RCM studyprocess, wherein the trigger mechanism process receives input from themaintenance repair organisation process and provides input to thebaseline review process, the continuous review process, and the RCMstudy process; v) performing the update process to provide update datafor performing the RCM; and vi) inputting the update data into theperforming of the RCM.
 9. A program stored on a non-transitorycomputer-readable medium or plurality of programs stored on anon-transitory computer-readable medium that will, when executed by acomputer system or one or more processors, cause the computer system orthe one or more processors to perform the method of claim 1.